Open source software defined radio transceiver

As the year draws to a close, we must look back and look at the advances in amateur radio this year. The RTL-SDR tuner hack, a USB TV Tuner to create a software defined radio receiver, is one of the greatest hacks of the last 12 months and a great justification for 2012 being the year of software defined radio receivers. 2013 is shaping up to have even more advances in the state of software defined radio. This time we’ll be transmitting as well, possibly with [AE9RB]’s Peaberry SDR transceiver.

The Peaberry SDR transceiver is a kit to both transmit and receive on every HAM band between 160 meters (1.8 MHz) to 17 meters (18 MHz). It does this through a USB interface and a 48kHz, 24-bit interface that is (or will shortly be) compatible with all the major SDR interfaces.

While the Peaberry SDR requires an amateur radio license to operate, we can’t wait to see what else will be coming to the software defined radio scene in the next year.

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29 thoughts on “Open source software defined radio transceiver”

Offtopic but related: Let’s say i have an old analog TV card. Would it be possible to decode digital broadcasts by software (the card has no MPEG2 chip but can recieve radio btw)? Yes, USB TV sticks are dirt cheap, but this question is in my mind for quite some time already.

Cheers to clever programmers bringing new uses to cheap or old hardware.

That idea worked with USB sticks used in RTLSDR because the chip had a mode it could go into where it just dumps a raw stream of data from the analog to digital converter straight to the computer. This isn’t even it’s normal mode of operation. Used as intended some work is done in the USB stick itself. You actually can’t even receive digital TV through it when using it as an SDR because it can’t push that much raw data to the computer fast enough through the usb port.

If you are using a card, not USB you might be able to get more bandwidth since you can push more data, faster from the card to the PC. You might actually be able to pull it off but… the chipset on your card would have to have a mode where it pushes raw data from the ADC. i believe you would be completely on your own to find this mode and write a driver to exploit it. If you do then please share!

* it’s a HF band device, it will require you to get an amateur radio licence
* it will require you to develop a digital telemetry protocol on a PC , raspi, etc
* moreover, HF bands are NOT AT ALL done for telemetry, they are made for narrow band modes such as CW, voice or specific digital modes. They require to be used with some etiquette or code of conduct, which is not to bother other users that may be engaged in long-range, weak signal communications (DX)

You should use an ISM module, that one will work only in a dedicated ISM band (433 or 868 MHz (europe) or 900 MHz (us)), it will not require you to get any licence and will not bother anyone. And it will be much cheaper than this one!

Sure there is telemetry on HF! Ocean buoys use it all the time! There is even telemetry on HF in the form of HF APRS!

That being said, it would be very bad form to use HAM BAND HF for this kind of telemetry. You really only need to reach one digipeater which is or can forward your packet to one iGate and then your data is available from pretty much anywhere. With HF your packet could be received at every digipeater at the same time across 1/2 the planet or more! That means for that moment nobody else’s packets are getting through.

Also, IANAL but legally I believe this would be considered an auxiliary station. At least in the US those are not allowed below the 2-meter band (maybe that’s not where you are though).

I would use 2-meter APRS. Even there it’s not polite to send position reports on the main frequency too often, there are alternate frequencies for that. Ideally I would want to send telemetry every 15 minutes or less on the main frequency at a low power and some shorter interval on the alternate. I’m not sure if there are trackers that will do this on the box but make or mod one, this is HaD!

Some would argue against ever transmitting on the main frequency so do so at your own risk. The thing is though.. on the alternate frequencies you are on your own to receive. If it’s out of range nobody else’s digipeater is going to help you. Also, you aren’t sharing. What kind of ham doesn’t find somebody’s near space balloon project interesting?!?! I know I would be happy to be playing around with APRS and see some local hacker’s balloon flying by. Plus, so long as you reach an iGate, and you probably will, anyone on the internet can watch!

Can anybody imagine there ever being enough amateur near space balloons at any one time to clog up the VHF APRS network at one report each, every 15 minutes?

One other thing regarding VHF APRS, although it is in the 2-meter band, where auxiliary stations are allowed it is in a section of 2-meters where auxiliary stations are not allowed. My understanding is that there is some sort of exception for APRS. I would want to find out more about this before launching the balloon.

You will need an amateur licence to start. It is not common to use the HF band for telemetry but it can be done with great results because the ionosphere reflecting the signal and the incredible height above everything. A quick google showed a project that would send back data by CW morse code, teletype and a oldschool teletype/fax and a Polish balloon project’s telemetry that was picked up in Canada.

But, the kit is $120, you’ll need a computer to work it so another $40 for a raspi and lots of development time to make it work. (and the time to study for and get the licence)

I recommend getting the licence to start because there don’t seem to be any inexpensive systems that will fit your requirements and the amateur licence learning materials are excellent. Plus you get access to a community that can help and the fundamentals to figure out the best solution.

This design is than the Softrock Ensemble Tx/Rx in that it has the sound chip on board. This might be a decent board for use with laptops which typically have lousy built-in sound specifications. The $129 price is decent – not dirt-cheap, as in the seller gets nothing back – and not outrageously high, like so many SDR products out there.

There are lots of problems with this design though (IMHO):

* No port isolation, so the possibility for ground loops exists unless you use external speakers and mic and only connect the radio to the PC via the USB port. If you connect any of the analog I/O ports to a PC, you’re asking for ground loop issues. The USB port should be isolated.

* Single ended output op-amps. Differential op-amps would have mitigated some of the nasty performance hits that come to direct-conversion SDR designs like this due to antenna mismatch (refer to Youngblood’s SDR for the masses papers).

* No optional (switchable better) input attenuator for use on the low frequency bands.

* No filter switching, which limits the frequency coverage. Adding filter switching would have added modestly to the cost while providing full HF general coverage.

* Why is the bandwidth limited to 48KHz? The PCM3060 sound chip is capable of 192KHz sample rate, so the bandwidth should be 96KHz. Maybe it’s because the of the limited capability of the on-board PSoC micro-controller?

* It looks like the firmware/software is locked-up tight.

* The Si570 quadrature clock division is being done inside the PSoC chip. Even if it is being done in programmable PSoC hardware, I would still keep anything involving clock division away from the micro-controller, lest open the door for introducing jitter. Adding a separate dual flip flop chip to do the division would have been trivial in terms of cost and complexity.

The “software defined” part makes it particularly special. And radios are not simple anyway, despite many of the concepts being around for a long time, designing a good transceiver is still a complex task.

Radio is alive and doing quite well thank you.
You’re probably using a radio to post that comment (wi-fi? Smart phone? Internet backbone microwave relay?)
This is just a longer range version that you can hold in your pocket.

If the idea of a radio is a black box where power comes in one side and music comes out the other then it makes no difference what is in that box.

In this case a software defined radio is an entire tool kit of radio parts giving access to all the different modulations and protocols and even to do measurements that were only available with specialty equipment until recently. It was one thing to be told about FM, the band width it uses and how it relates to volume and another to see a commercial FM station using it’s full channel vs the local collage station interviewing someone and then see how the FRS radios use just a sliver of that.

-this module is half useless, it does not even cover all the HF bands. that’s pretty disappointing. And very expensive given its reduced functionnalities.

Your argument is plain crap. How did you figure this is expensive ? Please point us to a sdr that remotely comes close to this price, keep in mind this is based on softrock txrx that is even half of the price. And please, no flex or other similar junk that nobody can afford anyway.

I wonder if more makers/hackers would be interested if some SDRs were either sold, or project plans online for the license free part 15 hifer or lowfer bands? Legal power output is low and antennas are restricted but using either really slow digital modes or ocasional atmospheric conditions and a lot of luck some reasonably long distances can be obtained. I’d like to see part-15 stations in every hackerspace as well as many maker’s homes. That might be an excelent gateway to licensed ham radio.

Simple, Cheap, Good: Pick Two.
With SDR, you can offload SOME of the complexity by requiring a specific program on the attached PC. You can also specify the soundcard as input, offloading complexity on the soundcard manufacturer.
This particular SDR splits the coverage into bands, then requires you to custom build for ONE specific band. Whether the final product is Simple, Cheap or Good enough is a matter of personal taste.

Hey, just out of curiosity. I’m trying to use the Realtec RTL2832U receiver and Elonics E4000 tuner in order to pick up digital tv signals. What are the requirements to make that happen? I’m kinda new to this!